The present invention relates to a device for providing a quick coupling between a tube and a rigid element such as the body of a pneumatic or a hydraulic component.
Coupling devices are known that comprise a tubular endpiece subdivided along its axis into a first portion for connection to the tube and a second portion for coupling to the element, and fastner means for fastening the tube to the endpiece and means for fastening the endpiece to the element, the second portion of the endpiece possessing a groove for receiving a gasket that is to provide sealing between said second portion of the endpiece and the element.
During storage and transport, and during the various handling operations to which the coupling device is subjected prior to being installed, the sealing gasket is either unprotected and thus runs the risk of being degraded, or else is protected by a plug which gives rise to extra cost and extra handling. Furthermore, in either case, the gasket is not protected during mounting proper and it can therefore sometimes happen that the gasket becomes damaged by rubbing against a projecting portion of the element.
The object of the invention is to design a coupling device of the above-specified type that incorporates means for protecting the sealing gasket, which means are effective both before mounting and during mounting.
According to the invention, this object is achieved by providing for the endpiece to be equipped with a protective sleeve for protecting the gasket, which sleeve is mounted on the second portion of the endpiece to slide along the axis of the endpiece between a position where it covers the groove, in which position it protects the gasket housed in said groove before and during coupling of the endpiece to the element, and a disengaged position which is offset from the groove towards the first portion of the endpiece so as to make it possible, prior to coupling, for the gasket to be put into place in the groove, and after coupling for the gasket to come directly into contact with the element.
Thus, prior to mounting, the sealing gasket is placed in the groove of the second portion of the endpiece and the protective sleeve is placed in a position where it overlies said groove so as to protect the gasket from any external attack throughout the various stages in which the endpiece is stored, transported, and handled. During mounting, the gasket is still protected by the protective sleeve until the portion of the element which is designed to co-operate with the gasket in order to seal the coupling automatically pushes the protective sleeve into its disengaged position so as to take the place it used to occupy and thus come into direct contact with the gasket. This ensures that the gasket is protected continuously.
According to a first advantageous characteristic of the invention, the protective sleeve is prevented from moving axially over the second portion of the endpiece while it is in an initial, waiting position by weak locking means. This ensures that during transport or any other handling of the coupling device, the protective sleeve does not move in untimely manner relative to the second portion of the endpiece, since that would run the risk of putting it in a position that is undesirable for the operator and/or the machine that is to put the gasket into place in the groove.
In which case, it is advantageous for the protective sleeve to be made integrally with the second portion of the endpiece and for the locking means to consist in a zone linking the protective sleeve to the second portion of the endpiece, which zone is mechanically weak. The endpiece and the protective sleeve are thus manufactured and the sleeve is put into place on the endpiece, in a single operation, thereby simplifying manufacture and reducing cost.
According to another advantageous characteristic of the invention, the second portion of the endpiece possesses a shoulder which forms an abutment for the protective sleeve in its disengaged position. The sliding of the protective sleeve towards the first portion of the endpiece is thus limited, thereby firstly facilitating handling operations on said protective sleeve both while installing the gasket and during a coupling operation, and secondly enabling the protective sleeve itself to act as an abutment for the portion of the element which comes into contact with the gasket and which pushes said sleeve into its disengaged position, bringing it into abutment against the shoulder of the second portion of the endpiece.
Other characteristics and advantages of the invention will appear on reading the following description of a particular embodiment, given by way of non-limiting example.